The study is the most extensive and sensitive planetary census of its kind. Astronomers used the W.M. Keck Observatory in Hawaii for five years to search 166 sun-like stars near our solar system for planets of various sizes, ranging from three to 1,000 times the mass of Earth.

All of the planets in the study orbit close to their stars. The results show more small planets than large ones, indicating small planets are more prevalent in our Milky Way galaxy.

"We studied planets of many masses -- like counting boulders, rocks and pebbles in a canyon -- and found more rocks than boulders, and more pebbles than rocks. Our ground-based technology can't see the grains of sand, the Earth-size planets, but we can estimate their numbers," said Andrew Howard of the University of California, Berkeley, lead author of the study. "Earth-size planets in our galaxy are like grains of sand sprinkled on a beach -- they are everywhere," Howard said.

The study is in the Oct. 29 issue of the journal Science.

The research provides a tantalizing clue that potentially habitable planets also could be common. These hypothesized Earth-size worlds would orbit farther away from their stars, where conditions could be favorable for life. NASA's Kepler spacecraft also is surveying sun-like stars for planets and is expected to find the first true Earth-like planets in the next few years.

Howard and his planet-hunting team, which includes principal investigator Geoff Marcy, also of the University of California, Berkeley, looked for planets within 80-light-years of Earth, using the radial velocity, or "wobble," technique.

They measured the numbers of planets falling into five groups, ranging from 1,000 times the mass of Earth, or about three times the mass of Jupiter, down to three times the mass of Earth. The search was confined to planets orbiting close to their stars -- within 0.25 astronomical units, or a quarter of the distance between our sun and Earth.

The ground where NASA's Mars Exploration Rover Spirit became stuck last year holds evidence that water, perhaps as snow melt, trickled into the subsurface fairly recently and on a continuing basis.

Stratified soil layers with different compositions close to the surface led the rover science team to propose that thin films of water may have entered the ground from frost or snow. The seepage could have happened during cyclical climate changes in periods when Mars tilted farther on its axis. The water may have moved down into the sand, carrying soluble minerals deeper than less soluble ones. Spin-axis tilt varies over timescales of hundreds of thousands of years.

The relatively insoluble minerals near the surface include what is thought to be hematite, silica and gypsum. Ferric sulfates, which are more soluble, appear to have been dissolved and carried down by water. None of these minerals are exposed at the surface, which is covered by wind-blown sand and dust.

"The lack of exposures at the surface indicates the preferential dissolution of ferric sulfates must be a relatively recent and ongoing process since wind has been systematically stripping soil and altering landscapes in the region Spirit has been examining," said Ray Arvidson of Washington University in St. Louis, deputy principal investigator for the twin rovers Spirit and Opportunity.

Analysis of these findings appears in a report in the Journal of Geophysical Research published by Arvidson and 36 co-authors about Spirit's operations from late 2007 until just before the rover stopped communicating in March.

The twin Mars rovers finished their three-month prime missions in April 2004, then kept exploring in bonus missions. One of Spirit's six wheels quit working in 2006.

In April 2009, Spirit's left wheels broke through a crust at a site called "Troy" and churned into soft sand. A second wheel stopped working seven months later. Spirit could not obtain a position slanting its solar panels toward the sun for the winter, as it had for previous winters. Engineers anticipated it would enter a low-power, silent hibernation mode, and the rover stopped communicating March 22. Spring begins next month at Spirit's site, and NASA is using the Deep Space Network and the Mars Odyssey orbiter to listen if the rover reawakens.

Star KIC 11026764, according to the NASA article NASA'S Kepler Spacecraft Takes Pulse Of Distant Stars, “…has the most accurately known properties of any star in the Kepler field. In fact, few stars in the earth are known to similar accuracy.""At an age of 5.94 billion years, it has grown to a little over twice the diameter of the sun and will maintain to do so as it transforms into a red giant. The oscillations reveal that this star is powered by hydrogen fusion in a thin shell around a helium-rich core."

Dr. Thomas Kallinger (Universities of British Columbia and Vienna), one of the scientists participating in the Keper studies, stated, "We are just about to enter a new part in stellar astrophysics. Kepler provides us with data of such good quality that they will vary our view of how stars work in detail."

he globular star cluster Omega Centauri has caught the attention of sky watchers ever since the ancient astronomer Ptolemy first catalogued it 2,000 years ago. Ptolemy, however, thought Omega Centauri was a single star. He didn't know that the "star" was actually a beehive swarm of nearly 10 million stars, all orbiting a common center of gravity.

The stars are so tightly crammed together that astronomers had to wait for the powerful vision of NASA's Hubble Space Telescope to peer deep into the core of the "beehive" and resolve individual stars. Hubble's vision is so sharp it can even measure the motion of many of these stars, and over a relatively short span of time.

A precise measurement of star motions in giant clusters can yield insights into how stellar groupings formed in the early universe, and whether an "intermediate mass" black hole, one roughly 10,000 times as massive as our Sun, might be lurking among the stars.

Analyzing archived images taken over a four-year period by Hubble's Advanced Camera for Surveys, astronomers have made the most accurate measurements yet of the motions of more than 100,000 cluster inhabitants, the largest survey to date to study the movement of stars in any cluster.

The International Space Station’s Expedition 25 crew Monday prepared for the arrival of the STS-133 space shuttle mission next month. Flight Engineer Scott Kelly gathered tools that will be used during two spacewalks to be performed by STS-133 Mission Specialists Tim Kopra and Alvin Drew. Commander Doug Wheelock inspected the hatches in the U.S. segment of the orbital complex, and controllers on the ground moved the Dextre remote manipulator system onto a power and data grapple fixture on the Destiny Laboratory in advance of the installation of the Permanent Multipurpose Module that will be delivered by the shuttle crew.

STS-133 is slated to begin with the launch of space shuttle Discovery Nov. 1 from Kennedy Space Center, Fla.

Space shuttle Discovery's payload for its STS-133 mission to the International Space Station is at Launch Pad 39A where workers will load it into the shuttle's payload bay. Discovery will carry the Permanent Multipurpose Module to the station during the upcoming mission. The module, which will remain attached to the station after Discovery leaves, is loaded with spare equipment, experiments, supplies and Robonaut 2, the first humanoid robot to go into space. Launch is targeted for Nov. 1 at 4:40 p.m. EDT.

The Soyuz spacecraft that will carry three new Expedition 25 flight engineers to the International Space Station was rolled out to the launch pad at the Baikonur Cosmodrome in Kazakhstan on Tuesday. NASA astronaut Scott Kelly and Russian cosmonauts Alexander Kaleri and Oleg Skripochka will launch aboard the new Soyuz TMA-01M Thursday at 7:10 p.m. EDT (Friday, Kazakhstan time) and begin a five-month tour of duty aboard the station after docking to the Poisk module Saturday evening.

Meanwhile, the three Expedition 25 crew members already living and working aboard the station conducted a depressurization drill, collected data for science research and prepared for the installation of a device to produce water.

Commander Doug Wheelock began his workday early by participating in the Pro K experiment, which studies dietary countermeasures to lessen the bone loss experienced by astronauts during long-duration spaceflight. With assistance from Flight Engineer Shannon Walker, Wheelock collected a blood sample and stored it in the Minus Eighty-Degree Laboratory Freezer for ISS for study later by scientists back on Earth.

During space shuttle Discovery's final spaceflight, the STS-133 crew members will take important spare parts to the International Space Station along with the Express Logistics Carrier-4. Discovery has been moved to Launch Pad 39A at NASA's Kennedy Space Center in Florida. STS-133 is slated to launch Nov. 1.